This is where the magic happens. Every option has built in documentation that appears by hovering the mouse over it. Play with different options and continue to improvise using the preview.
Transition In
These settings apply to the Layer when it's about to appear on the slide. For example, OffsetX and OffsetY determines the location from where the Layer will appear in. Duration determines how long will it take to appear and Delay determines how long it will wait before transitioning in.
Transition Out
These settings apply to the Layer when it's ready to leave the slide. Show Until determines how long the layer is visible on the slide. Use a value of 0 if you do not want the layer to disappear.
Other Options
Simply change the Parallax Level by incrementing the number and see the preview and mouse interaction. A hidden layer does not appear on the slide.